BACKGROUND: Prior clinical trials suggest that the Transcendental Meditation technique may decrease blood pressure of normotensive and hypertensive individuals but study-quality issues have been raised. This study was designed to assess effects of Transcendental Meditation on blood pressure using objective quality assessments and meta-analyses. METHODS: PubMed and Cochrane databases through December 2006 and collected publications on Transcendental Meditation were searched. Randomized, controlled trials comparing blood pressure responses to the Transcendental Meditation technique with a control group were evaluated. Primary outcome measures were changes in systolic and diastolic blood pressure after practicing Transcendental Meditation or following control procedures. A specific rating system (0-20 points) was used to evaluate studies and random-effects models were used for meta-analyses. RESULTS: Nine randomized, controlled trials met eligibility criteria. Study-quality scores ranged from low (score, 7) to high (16) with three studies of high quality (15 or 16) and three of acceptable quality (11 or 12). The random-effects meta-analysis model for systolic and diastolic blood pressure, respectively, indicated that Transcendental Meditation, compared to control, was associated with the following changes: -4.7 mm Hg (95% confidence interval (CI), -7.4 to -1.9 mm Hg) and -3.2 mm Hg (95% CI, -5.4 to -1.3 mm Hg). Subgroup analyses of hypertensive groups and high-quality studies showed similar reductions. CONCLUSIONS: The regular practice of Transcendental Meditation may have the potential to reduce systolic and diastolic blood pressure by approximately 4.7 and 3.2 mm Hg, respectively. These are clinically meaningful changes.